diff --git a/packages/block-library/src/more/block.json b/packages/block-library/src/more/block.json
index b071f6ba5d7ef..d1153ca4f1689 100644
--- a/packages/block-library/src/more/block.json
+++ b/packages/block-library/src/more/block.json
@@ -9,7 +9,8 @@
 	"textdomain": "default",
 	"attributes": {
 		"customText": {
-			"type": "string"
+			"type": "string",
+			"default": ""
 		},
 		"noTeaser": {
 			"type": "boolean",
diff --git a/packages/block-library/src/more/edit.js b/packages/block-library/src/more/edit.js
index 6b5dc59a13554..bcad7ec1b8366 100644
--- a/packages/block-library/src/more/edit.js
+++ b/packages/block-library/src/more/edit.js
@@ -10,14 +10,13 @@ import { getDefaultBlockName, createBlock } from '@wordpress/blocks';
 const DEFAULT_TEXT = __( 'Read more' );
 
 export default function MoreEdit( {
-	attributes: { customText = '', noTeaser },
+	attributes: { customText, noTeaser },
 	insertBlocksAfter,
 	setAttributes,
 } ) {
 	const onChangeInput = ( event ) => {
 		setAttributes( {
-			customText:
-				event.target.value !== '' ? event.target.value : undefined,
+			customText: event.target.value,
 		} );
 	};